Negative mass of matter. Big encyclopedia of oil and gas

Researchers from the University of Washington (USA) have achieved from rubidium atoms the behavior of a substance with a negative effective mass. This means that these atoms did not fly in the direction of the vector of this influence under external influence. Under the experimental conditions, they behaved as if they ran into an invisible wall every time they approached the boundaries of a region with a very small volume. The corresponding one is published in Physical Review Letters. The experiment was misinterpreted by the media as "creating matter with negative mass" (in theory, it allows you to create wormholes for distant space travel). In fact, obtaining a substance with a negative mass, if possible, is far beyond what is achievable for modern science and technologies.

Rubidium atoms were forced to move in the direction opposite to the vector of the force applied to them. The media misinterpreted this as the creation of a substance with a "negative mass"

The authors of the work slowed down rubidium atoms with a laser (a decrease in the speed of a particle means its cooling). At the second stage of cooling, the most energetic atoms were allowed to leave the cooled volume. This cooled him even more, the way the evaporation of refrigerant atoms cools the contents of a domestic refrigerator. At the third stage, a different set of lasers was used, the pulses of which changed the spin (simplified, the direction of rotation around own axis) parts of atoms.

Since some atoms in the cooled volume continued to have a normal spin, while others received a reverse one, their interaction with each other acquired an unusual character. In normal behavior, rubidium atoms colliding would fly apart in different sides. The central atoms would push the outer ones outward, accelerating them in the direction of the force application (the motion vector of the first atom). Due to the inconsistency in spins, in practice, rubidium atoms cooled to small fractions of a kelvin did not fly apart after collisions, remaining in the initial volume, equal to about a thousandth of a cubic millimeter. From the outside, it looked like they were hitting an invisible wall.

A very distant analogy for a group of atoms with different spins - a collision of two or more soccer balls, side impact pre-twisted before rotating around its axis in different directions. It is clear that the directions and speeds of their movement after the collision will differ significantly from the same results for ordinary balls. But this does not mean that the balls have changed their physical mass. Only the nature of their interaction with each other has changed. Also in the experiment, the mass of atoms did not become negative. In a gravitational field, they would still go down. What really changed was only where they moved after collisions with other similar atoms, but "rotating" around their axis in the other direction.

The behavior of rubidium atoms in the experiment corresponds to the definition of negative effective mass in physics. It is used, for example, in describing the behavior of an electron in crystal lattice. For him, the formal mass depends on the direction of motion relative to the axes of the crystal. Moving in one direction, it will show one variance (scattering), in the other - another. The concept of effective mass was introduced for them because otherwise, when describing their scattering by formulas, the mass would begin to depend on energy, which is not very convenient for calculations. An example of a negative effective mass is the behavior of holes in semiconductors, which every user of modern electronics has to deal with.

Most of the media, including Russian ones, interpreted the experiment as creating a substance with a negative mass. In theory, matter with similar properties could be used to keep wormholes in working order, allowing long-range travel in space and time in near-zero time. The practical possibility of creating such a substance, as well as the wormholes themselves, has not yet been proven. Even if it is possible, it is unrealistic to obtain it with the modern technical capabilities of mankind.

AT theoretical physics, negative mass is the concept of a hypothetical substance whose mass has the opposite value of mass normal matter(just like an electric charge can be positive and negative). For example, -2 kg. Such matter, if it existed, would violate one or more energetic conditions and exhibit some strange properties. According to some speculative theories, negative mass matter can be used to create wormholes ( wormholes) in space-time.

Sounds like absolute fantasy, but...

For the first time in the history of science, physicists from the University of Washington have recreated the conditions under which matter, a certain kind of liquid, exhibits the properties of "negative mass". The behavior of this fluid is fully consistent with the concept of a negative mass, when a force vector acting in a certain direction is applied to it, this fluid begins to move with acceleration in the opposite direction. Such an effect is difficult to obtain even in the laboratory, "but it can be used to study and explain some previously unexplained astrophysical phenomena," explains Michael Forbes, professor of physics and astronomy at the University of Washington.

From a hypothetical point of view, matter can have negative mass in the same way that electric charges have positive or negative polarity. People very rarely think about this aspect, because in the world around us only the "positive" side of the mass is manifested. According to Newton's second law, if you apply a constant force to an object, it will move with constant acceleration in the direction of this force.

“On the basis of Newton’s Second Law, almost everything that we see around us operates,” says Michael Forbes, “However, matter with negative mass reacts to the force applied to it in an absolutely opposite way, it begins to move in the direction of the force applied to it.”


Figure 1. Anisotropic expansion of a Bose-Einstein condensate with different coefficients adhesion forces. Real Results experiments are in red, prediction results in simulation are in black

The bottom chart is an enlarged section of the middle frame in the bottom row of Figure 1. The bottom chart shows a 1D simulation of total density versus time in the region where dynamic instability first appeared.

The so-called Bose-Einstein condensate, a cloud of rubidium atoms cooled almost to a temperature absolute zero. Under such conditions, the thermal motion of particles practically stops and, thanks to the forefront of the laws quantum mechanics, this cloud of atoms acquires wave function and behaves like one big solid atom. In addition, the Bose-Einstein condensate, due to the synchronous movement of atoms, has the properties of a superfluid, a superfluid liquid, the viscosity coefficient of which is zero.

With the help of laser light with certain parameters, scientists slowed down rubidium atoms almost to a complete stop, and those "hot" atoms that could not be slowed down were expelled from the trap space using the same laser light. The trap into which the Bose-Einstein condensate was "driven" had a spherical shape and a size of only 100 microns. At this moment, the condensate still had the usual "positive" mass, but the intentional violation of the integrity of the trap led to the violation of the ideal spherical shape of the condensate, and the rubidium atoms rushed out of the trap.

And at that moment the most interesting began. The scientists used a set of additional lasers that changed the direction of rotation of the rubidium atoms. And after such "treatment" the condensate superfluid acquired the properties of a negative mass. "As soon as the atoms reach the boundary of the mass transition from the positive to the negative region, they accelerate sharply in reverse direction"- says Michael Forbes, - "It's like rubidium atoms are reflected from an invisible wall."

The above technique for obtaining matter with a "negative" mass allowed scientists to avoid some of the problems and troubles that scientists encountered during previous similar attempts. "Thanks to the complete and precise control of all the parameters of the experiment, we were able to recreate the conditions under which a clear boundary of the "reversal of polarity" of the mass of matter appears in the experimental area," says Michael Forbes, "Something similar can occur in the depths of exotic astronomical objects, such as like neutron stars, black holes and dense clusters dark matter. Now we have the opportunity to experiment and simulate in the laboratory fundamental phenomena that occur only in a very specific environment the above space objects"

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But we are already being promised that soon the Self-flowing liquid will flow into the taps by itself, and now we are having the Sixth Extinction. Not so long ago, an artificial brain was grown and, for the first time, organs were successfully frozen and thawed.

Saved

Hypothetical wormhole in spacetime

In the laboratory of the University of Washington, conditions were created for the formation of a Bose-Einstein condensate in a volume of less than 0.001 mm³. The particles were slowed down by a laser and waited for the most energetic of them to leave the volume, which further cooled the material. At this stage, the supercritical fluid still had a positive mass. In the event of a leak in the vessel, the rubidium atoms would scatter in different directions, since the central atoms would push the extreme atoms outward, and they would accelerate in the direction of the application of force.

To create a negative effective mass, physicists used a different set of lasers that changed the spin of some atoms. As the simulation predicts, in some areas of the vessel, the particles should acquire a negative mass. This is clearly seen in the sharp increase in the density of matter as a function of time in the simulations (in the lower diagram).


Figure 1. Anisotropic expansion of a Bose-Einstein condensate with different cohesive force coefficients. The real results of the experiment are in red, the results of the prediction in the simulation are in black

The bottom diagram is an enlarged section of the middle frame in the bottom row of Figure 1.

The bottom diagram shows a 1D simulation of total density versus time in the region where dynamic instability first appeared. Dotted lines separate three groups of atoms with velocities at the quasi-momentum , where the effective mass starts to become negative (upper line). The point of minimum negative effective mass is shown (middle) and the point where the mass returns to positive values ​​(bottom line). The red dots indicate the places where the local quasi-momentum lies in the region of the negative effective mass.

The very first row of graphs shows that during physical experiment the matter behaved in exact accordance with the results of the simulation, which predicts the appearance of particles with a negative effective mass.

In a Bose-Einstein condensate, particles behave like waves and therefore propagate in a different direction than normal particles of positive effective mass should propagate.

In fairness, it must be said that physicists repeatedly recorded results during experiments when the properties of matter of negative mass were manifested, but those experiments could be interpreted in different ways. Now the uncertainty is largely eliminated.

Scientific article published on April 10, 2017 in the journal Physical Review Letters(doi:10.1103/PhysRevLett.118.155301, available by subscription). A copy of the article before sending it to the journal was posted on December 13, 2016 at free access at arXiv.org (arXiv:1612.04055).

Recommended to watch at 1280 x 800 resolution


"Technique-youth", 1990, No. 10, p. 16-18.

Scanned by Igor Stepikin

Tribune of bold hypotheses

Ponkrat BORISOV, engineer
Negative Mass: Free Flight to Infinity

  • Articles on this topic have been appearing in foreign and Soviet physics journals from time to time for more than 30 years. But oddly enough, they still do not seem to have attracted the attention of popularizers. But the problem of negative mass, and even in strictly scientific setting- a great gift for lovers of the paradoxes of modern physics, and science fiction writers. But such is the property special literature: the sensation in it can remain hidden for decades ...
  • So, we are talking about a hypothetical form of matter, the mass of which is opposite in sign to the usual one. The question immediately arises: what does this actually mean? And it immediately becomes clear: it is not so easy to correctly define the concept of negative mass.
  • Undoubtedly, it must have the property of gravitational repulsion. But it turns out that this alone is not enough. In modern physics, four types of mass are strictly distinguished:
  • gravitational active - the one that attracts (if it is positive, of course);
  • gravitational passive - the one that is attracted;
  • inert, which acquires a certain acceleration under the action of an applied force (a \u003d F / m);
  • finally, Einstein's rest mass, which sets the total energy of the body (E = mC 2).
  • In the framework of generally accepted theories, they are all equal in magnitude. But it is necessary to distinguish between them, and this becomes clear just when trying to determine the negative mass. The fact is that it will be completely opposite to the usual one only if all four of its types become negative.
  • Based on this approach, in the very first article on this topic, published back in 1957, English physicist X. Bondy determined the basic properties of "minus-mass" by rigorous proofs.
  • It may not even be very difficult to repeat them here, because they are based only on Newtonian mechanics. But this will clutter up our story, and then there are a lot of physical and mathematical "subtleties". Therefore, let's go straight to the results, especially since they are quite clear.
  • Firstly, “minus matter” must gravitationally repel any other bodies, that is, not only with negative, but also with positive mass (whereas ordinary matter, on the contrary, always attracts matter of both types). Further, under the action of any force, up to the force of inertia, it must move in the direction opposite vector this strength. And finally, its total Einstein energy must also be negative.
  • Therefore, by the way, it should be emphasized that our amazing matter- not antimatter, the mass of which is still considered positive. For example, by modern ideas, "Anti-Earth" from antimatter would revolve around the Sun in exactly the same orbit as our home planet.
  • All this is almost obvious. But then the incredible begins.
  • Let's take the same gravity. If two ordinary bodies attract and approach each other, and two antimasses repel each other and scatter, then what happens during the gravitational interaction of masses of different signs?
  • Let it be simplest case: a body (say, a ball) made of matter with a negative mass -M is behind an object (let's call it a "rocket" - now we'll find out why) with an equal positive mass +M. It is clear that the gravitational field of the ball repels the rocket, while it itself attracts the ball. But it follows from here (this is again strictly proved) that the whole system will move along a straight line connecting the centers of two masses, with a constant acceleration proportional to the strength of the gravitational interaction between them!
  • Of course, at first glance, this picture of spontaneous, causeless motion “proves” only one thing: antimass with the properties that we attributed to it in the definition from the very beginning simply cannot exist. After all, we have received, it would seem, a whole bunch of violations of the most immutable laws.
  • Well, isn't the law of conservation of momentum, for example, being completely openly violated here? Both bodies, for no reason at all, rush in the same direction, while nothing moves in the opposite direction. But remember that one of the masses is negative! But this means that its impulse, regardless of speed, has a minus sign: (-M) V, and then total impulse two-body system is still zero!
  • The same is true for the total kinetic energy of the system. While the bodies are at rest, it is equal to zero. But no matter how fast they move, nothing changes: the negative mass of the ball, in full accordance with the formula (-M)V 2 /2, accumulates negative kinetic energy, which exactly compensates for the increase positive energy rockets.
  • If all this seems absurd, then maybe we will “knock out a wedge with a wedge” - let's try to confirm one absurdity with another? Since the sixth grade, we know that the center of equal point masses (positive, of course) is in the middle between them. So - how would you like the following output? The center of equal point masses of DIFFERENT SIGN lies, although on a straight line passing through them, but not inside, but OUTSIDE of the segment connecting them, at the point ±Ґ ?!
  • Well, is it easier?
  • By the way, this conclusion is already quite elementary, and everyone can repeat it if they wish, owning physics at the level of the same sixth grade.
  • Anyone who does not believe in a word and wants to make sure that all calculations are correct can refer to one of latest publications on this topic - article American physicist R. Forward "Rocket engine on the substance of negative mass", published in the translated magazine " Aerospace Engineering» No. 4 for 1990.
  • But, perhaps, the sophisticated reader thinks that even without any calculations he understood where the "linden" was slipped to him? Indeed: in all these elegant arguments, the question is hushed up: where did such a wonderful mass come from? After all, whatever its origin, it will take energy to “extract”, “manufacture” or, say, deliver it to the scene of action, which means ...
  • Alas, sophisticated reader! Energy, of course, will be needed, but again negative. Nothing can be done: in Einstein's formula for the total energy of the body E = Ms 2, our wonderful mass has the same minus sign. This means that the "production" of a pair of bodies with EQUAL masses of DIFFERENT signs will require ZERO total energy. The same applies to delivery, and to any other manipulations.
  • No - no matter how paradoxical all these results, strict conclusions state that the presence of antimass does not contradict not only Newtonian mechanics, but also general theory relativity. It was not possible to find any logical prohibitions on its existence.
  • Well - if the theory "allows", then let's think, for example, - what can happen when physical contact two identical particles of matter with plus and minus masses? With "ordinary" antimatter, everything is clear: annihilation will occur with the release of the total energy of both bodies. But if one of the two equal masses is negative, then their total energy, as we just understood, is zero. But WHAT will happen to them in reality - this is already a question that goes beyond the theory.
  • The outcome of such an event can only be known empirically. It is impossible to “calculate” it - after all, we have no idea about the “mechanism of action” of the negative mass, its “ internal arrangement”(as, however, we do not know this about the mass of the usual). Theoretically, one thing is clear: in any case, the total energy of the system will remain zero. We have the right to put forward only a HYPOTHESIS, as the same Forward does. According to his assumption, physical interaction here it does not lead to annihilation, but to the so-called "nullification", that is, the "quiet" mutual annihilation of particles, their disappearance without any release of energy.
  • But, we repeat, only an experiment could confirm or refute this hypothesis.
  • For the same reasons, we don't know anything about how to "make" negative mass (if at all possible). The theory only states that two equal masses opposite sign in principle, they can arise without any energy costs. And as soon as such a pair of bodies appears, it will fly, accelerating, in a straight line to infinity...
  • R. Forward in his article has already “designed” a negative mass engine that can take us to any point in the Universe at any acceleration that we set. It turns out that all that is needed for this is ... a pair of good springs (all interactions of the "minus-mass" with the usual one through elastic forces, of course, are also calculated in detail).
  • So, let's place our wonderful mass, equal in size to the mass of the rocket, in the middle of its "engine compartment". If you need to fly forward, stretch the spring from the back wall and hook its negative mass body. Immediately because of their "perverted" inertial properties it will rush not where it is pulled, but in the exact opposite direction, dragging the rocket along with it with an acceleration proportional to the force of the spring tension.
  • To stop acceleration, it is enough to unhook the spring. And to slow down and stop the ship, you need to use a second spring attached to the front wall of the engine compartment.
  • And yet there is a partial refutation of the "free engine"! True, it comes from a completely unexpected side. But more about that at the end.
  • In the meantime, let's look for places where there could be large amounts of negative mass. Such places are suggested by the giant voids found on large-scale three-dimensional maps of the distribution of galaxies in the Universe - phenomena that are most interesting in themselves. As can be seen from fig. 2, the dimensions of these cavities, which are also simply called "bubbles", are about 100 million light years (whereas the dimensions of our Galaxy are about 0.06 million light years). Thus, on the largest scale, the Universe has a "foamy" structure.
  • The boundaries of the bubbles are clearly marked by clusters a large number galaxies. There are practically no bubbles inside, and if they are found there, then these are very unusual objects. They are characterized by the spectra of powerful high-frequency radiation. It is now believed that the bubbles contain "failed" galaxies or gas clouds of ordinary hydrogen.
  • But is it possible to assume that the "foamy" structure of the Universe is the result of its formation from the same number of particles of negative and positive mass? By the way, a very attractive consequence follows from such an explanation: the total mass of the Universe has always been and remains equal to zero. Then the bubbles are natural places for minus-mass, the particles of which tend to disperse as far as possible from each other. And the positive mass is pushed to the surface of the bubbles, where, under the influence of gravity forces, it forms galaxies and stars. Here we can recall the article by A. A. Baranov, which appeared back in 1971 in No. 11 of the journal Izvestia Vuzov. Physics". There is considered cosmological model Universe with particles having masses of both signs. Using this model, the author explains the experimental estimates of the cosmological constant and the Hubble redshift, as well as some anomalous phenomena observed in interacting galaxies.
  • Another possible sign large quantities negative mass - the presence of very fast "currents" in large-scale structures of the Universe. Thus, the supercluster containing our Galaxy "flows" at a speed of 600 km/s relative to the background at rest. relic radiation. Such a speed does not fit into the framework of theories of the formation of galaxies from cold dark matter. R. Forward proposes to try to explain this phenomenon taking into account the collective repulsion of superclusters from bubbles containing negative mass.
  • So, negative matter can only scatter. But this, it turns out, is the partial refutation of many of the conclusions that were discussed. After all, the property of gravitational repulsion of particles of matter, whatever their nature, inevitably leads to the fact that these particles cannot come together under the influence of gravitational forces. Moreover, since a particle of negative mass under the action of any force moves in the direction opposite to the vector of this force, then ordinary interatomic interactions cannot bind such particles into “normal” bodies.
  • But we hope that the reader nevertheless received pleasure from all these arguments ...

    • ), even if these materials are created and relatively well studied.

    This can also be called a material created from some types of exotic atoms, in which the role of the nucleus (positively charged particle) is played by a positron (positronium) or a positive muon (muonium). There are also atoms with a negative muon instead of one of the electrons (the muonic atom).

    negative mass

    It can be seen that an object with a negative inertial mass will accelerate in the opposite direction to that in which it was pushed, which may seem strange.

    If we study the inertial mass, passive gravitational mass and active gravitational mass separately, then Newton's law of universal gravitation will take the following form:

    Thus, objects with negative gravitational mass (both passive and active), but with positive inertial mass, will be repelled by positive active masses and attracted by negative active masses.

    Forward Analysis

    Although negative mass particles are unknown, physicists (originally G. Bondy and Robert L. Forward (English) Russian ) were able to describe some of the expected properties such particles might have. Assuming that all three types of masses are equal, it is possible to construct a system where negative masses are attracted to positive masses, while positive masses are repelled by negative masses. At the same time, negative masses will create an attractive force towards each other, but will be repelled due to their negative inertial masses.

    At negative value and positive value, the force will be negative (repulsive). At first glance, it looks as if the negative mass would accelerate away from the positive mass, but since such an object would also have a negative inertial mass, it would accelerate in the opposite direction. Moreover, Bondy showed that if both masses are equal in absolute value, but differ in sign, then general system positive and negative particles will accelerate indefinitely without any additional influence on the system from outside.

    This behavior is strange in that it is completely inconsistent with our idea of ​​" ordinary universe from work with positive masses. But it is completely mathematically consistent and does not introduce any contradictions.

    It may seem that such a representation violates the law of conservation of momentum and / or energy, but we have the masses are equal in absolute value, one is positive and the other is negative, which means that the momentum of the system is zero if they both move together and accelerate together , regardless of speed:

    And the same equation can be calculated for kinetic energy:

    Forward extended Bondi's research to additional cases and showed that even if two masses and are not equal in absolute value, the equations still remain consistent.

    Some properties that are introduced by these assumptions look unusual, for example, in a mixture of gas from positive matter and gas from negative matter the positive part will increase its temperature indefinitely. However, in such a case negative part mixture will be cooled at the same rate, thus equalizing the balance. Geoffrey A. Landis (English) Russian noted other applications of Forward's analysis, including indications that although particles with negative mass will repel each other gravitationally, but electrical forces, for example, charges will attract each other (unlike particles with positive mass, where such particles repel each other). As a result, for particles with negative mass, this means that the gravitational and electrostatic forces are reversed.

    Forward proposed a design for the engine spaceships using negative mass, which does not require an influx of energy and a working fluid in order to obtain an arbitrarily large acceleration, although, of course, the main obstacle is that the negative mass remains completely hypothetical. See diametric drive.

    Forward also coined the term "nullification" to describe what happens when normal and negative matter meet. It is expected that they can mutually annihilate or "nullify" the existence of each other, and after that there will be no energy left. However, it is easy to show that some momentum can remain (it will not remain if they move in the same direction, as described above, but they need to move towards each other in order to meet and mutually nullify). This may, in turn, explain why equal amounts ordinary and negative matter do not suddenly appear out of nowhere (the opposite of nullification): in this event, the momentum of each of them will not be conserved.

    Exotic matter in general relativity

    In which direction does antimatter fall?

    Main article: Gravitational interaction of antimatter

    Majority modern physicists believes that antimatter has a positive gravitational mass and should fall down like ordinary matter. At the same time, however, some researchers believe that so far there are no convincing experimental evidence this fact. This is due to the difficulty direct research gravitational forces at the particle level. At such small distances, electrical forces take precedence over a much weaker gravitational interaction. Moreover, antiparticles must be kept separate from their conventional counterparts or they will quickly annihilate. Obviously this makes it difficult direct measurement passive gravitational mass antimatter. Experiments on antimatter ATHENA ATHENA ) and ATRAP (eng. ATRAP ) may soon provide answers.

    The answers for the inertial mass, however, have long been known from experiments with a bubble chamber. They convincingly show that antiparticles have a positive inertial mass, equal to the mass"ordinary" particles, but the opposite electric charge. In these experiments, the chamber is exposed to constant magnetic field, which causes the particles to move in a helix. The radius and direction of this movement correspond to the ratio electric charge to inert mass. Particle-antiparticle pairs move along helical lines in opposite directions, but with the same radii. From this observation, it is concluded that their ratios of electric charge to inertial mass differ only in sign.

    Notes

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